LCD monitors have been used as transparent light valves for certain products. The casino industry uses displays where the backlight has been modified to create slot machines where the tumblers are visible through a hole in the backlight. LCD panels have been used in overhead projection machines prior to the design of good low cost data projectors. LCD panels are used in LCD projectors where the light source is directed through the liquid crystal in order to project the image on a surface.
A company has demonstrated the application of layered LCD panels to create a three dimensional display. The application is currently limited by the inefficiency of the panels, however, new IGZO panel technology may reignite interest in these constructions.
Improvements in manufacturing techniques by companies such as Samsung have allowed for the creation of large transparent LCD panels with reasonable color reproduction and off axis viewing. These are intended for installation in the glass doors of refrigerators and in the windows of retail establishments. They can also be used in bus stops, at home, in offices, and so on. There are substantial opportunities for transparent displays alone or with touch screens.